Python 3.x Flask应用程序崩溃（最有可能是由于循环导入）

我在这里遵循了本教程：。这是一个非常简单的Flask应用程序，用于为站点创建用户登录和注册页面。在本教程中，所有内容都适用于这一点：当在项目中的脚本中导入对象时，我会遇到此错误

错误：

flask.cli.NoAppException
flask.cli.NoAppException: While importing "app", an ImportError was raised:

Traceback (most recent call last):
  File "c:\users\dejar\onedrive\coding\themes & applications\002 static template\install\env\lib\site-packages\flask\cli.py", line 240, in locate_app
    __import__(module_name)
  File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\app.py", line 6, in <module>
    from account import routes
  File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\account\routes.py", line 5, in <module>
    from app import app, now
ImportError: cannot import name 'app' from partially initialized module 'app' (most likely due to a circular import) (C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\app.py)

Traceback (most recent call last)
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\app.py", line 6, in <module>
from account import routes
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\account\routes.py", line 5, in <module>
from app import app, now
During handling of the above exception, another exception occurred:
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\env\Lib\site-packages\flask\cli.py", line 338, in __call__
self._flush_bg_loading_exception()
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\env\Lib\site-packages\flask\cli.py", line 326, in _flush_bg_loading_exception
reraise(*exc_info)
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\env\Lib\site-packages\flask\_compat.py", line 39, in reraise
raise value
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\env\Lib\site-packages\flask\cli.py", line 314, in _load_app
self._load_unlocked()
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\env\Lib\site-packages\flask\cli.py", line 330, in _load_unlocked
self._app = rv = self.loader()
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\env\Lib\site-packages\flask\cli.py", line 388, in load_app
app = locate_app(self, import_name, name)
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\env\Lib\site-packages\flask\cli.py", line 245, in locate_app
raise NoAppException(
flask.cli.NoAppException: While importing "app", an ImportError was raised:

Traceback (most recent call last):
File "c:\users\dejar\onedrive\coding\themes & applications\002 static template\install\env\lib\site-packages\flask\cli.py", line 240, in locate_app
__import__(module_name)
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\app.py", line 6, in <module>
from account import routes
File "C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\account\routes.py", line 5, in <module>
from app import app, now
ImportError: cannot import name 'app' from partially initialized module 'app' (most likely due to a circular import) (C:\Users\dejar\OneDrive\Coding\Themes & Applications\002 Static Template\Install\app.py)
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app.py

from flask import Flask, render_template

# account routes
from user import routes

# create and configure the app, an instance of Flask
app = Flask(__name__)


@app.route("/")
def home():
    return render_template("home.html")


@app.route("/dashboard/")
def dashboard():
    return render_template("dashboard.html")

from flask import Flask, jsonify


class User:
    def signup(self):
        user = {"_id": "", "name": "", "email": "", "password": ""}
        return jsonify(user), 200
        # if successful, return status code 200 in json format

from flask import Flask, render_template

# import the instance of app from app.py
# from file/module import instance
from app import app

# from folder.file import class
from user.models import User


@app.route("/user/signup", methods=["GET"])
def signup():
    return User().signup()

型号.py

from flask import Flask, render_template

# account routes
from user import routes

# create and configure the app, an instance of Flask
app = Flask(__name__)


@app.route("/")
def home():
    return render_template("home.html")


@app.route("/dashboard/")
def dashboard():
    return render_template("dashboard.html")

from flask import Flask, jsonify


class User:
    def signup(self):
        user = {"_id": "", "name": "", "email": "", "password": ""}
        return jsonify(user), 200
        # if successful, return status code 200 in json format

from flask import Flask, render_template

# import the instance of app from app.py
# from file/module import instance
from app import app

# from folder.file import class
from user.models import User


@app.route("/user/signup", methods=["GET"])
def signup():
    return User().signup()

routes.py

from flask import Flask, render_template

# account routes
from user import routes

# create and configure the app, an instance of Flask
app = Flask(__name__)


@app.route("/")
def home():
    return render_template("home.html")


@app.route("/dashboard/")
def dashboard():
    return render_template("dashboard.html")

from flask import Flask, jsonify


class User:
    def signup(self):
        user = {"_id": "", "name": "", "email": "", "password": ""}
        return jsonify(user), 200
        # if successful, return status code 200 in json format

from flask import Flask, render_template

# import the instance of app from app.py
# from file/module import instance
from app import app

# from folder.file import class
from user.models import User


@app.route("/user/signup", methods=["GET"])
def signup():
    return User().signup()

---

注意：init.py文件为空

错误消息

无法从部分初始化的模块“app”导入名称“app”

的意思是，当Python编译一个文件时，它需要编译另一个文件–要导入的模块。但是，第二个文件也需要读取导入，即原始的第一个文件。因此，python不能编译一个而不编译另一个

最好的解决方案是在app.py文件的端导入app.routes，如下所示：

从烧瓶导入烧瓶，在顶部渲染#模板#导入
#代码的其余部分
从应用程序导入路由

这应该可以解决问题

将app import app中的

保持在routes.py的顶部。请记住，应用程序目录中没有init.py可能会导致导入困难

编辑：

正如formerlyanakin所说，import语句不必位于文件的末尾。相反，它可以在初始化
app
后的任何位置进行定位：

app.py：

#创建并配置应用程序，Flask的一个实例
app=烧瓶（名称）
#客户路线
从用户导入路由
错误消息
无法从部分初始化的模块“app”导入名称“app”
的意思是，当Python编译一个文件时，它需要编译另一个文件–要导入的模块。但是，第二个文件也需要读取导入，即原始的第一个文件。因此，python不能编译一个而不编译另一个

最好的解决方案是在app.py文件的端导入app.routes，如下所示：

从烧瓶导入烧瓶，在顶部渲染#模板#导入
#代码的其余部分
从应用程序导入路由

这应该可以解决问题

将app import app中的
保持在routes.py的顶部。请记住，应用程序目录中没有init.py可能会导致导入困难

编辑：

正如formerlyanakin所说，import语句不必位于文件的末尾。相反，它可以在初始化
app
后的任何位置进行定位：

app.py：

#创建并配置应用程序，Flask的一个实例
app=烧瓶（名称）
#客户路线
从用户导入路由
您只做了一次调整就正确了。这真的很难让我理解。它不必位于我的app.py的页脚。我只需要在app.py文件中切换导入和应用实例的顺序。谢谢，格雷西亚斯。我是阿尤多·穆乔，你只做了一次调整就对了。这真的很难让我理解。它不必位于我的app.py的页脚。我只需要在app.py文件中切换导入和应用实例的顺序。谢谢，格雷西亚斯。我是阿尤多·穆乔